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Anti-CASPR2 Antibody Measurement by Immunoassay (CSF)

Published: August 9, 2026Updated: August 16, 2026

This test detects antibodies against the CASPR2 protein in cerebrospinal fluid (CSF). These antibodies are linked to certain autoimmune neurological conditions.

Quick summary

["This test helps diagnose or evaluate conditions like limbic encephalitis or other autoimmune-related neurological symptoms."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
109460-6
Short code
CASPR2CSF
Synonyms
CASPR2 Ab Msmt CSF
Category
chemistry
Sample
csf
Container
Sterile, screw-cap polypropylene collection tube (tube #3 or #4 of standard lumbar puncture collection series)
Units
N/A
Ref low
0
Ref high
1
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
Cell-based indirect immunofluorescence assay (CBA-IFA) or fixed cell-based assay; may also be performed by enzyme-linked immunosorbent assay (ELISA) or immunohistochemistry (IHC)
CPT
86255
SNOMED
407660008
Specimen volume
1-2 mL of cerebrospinal fluid; minimum 0.5 mL required for analysis
Stability
Room temperature: 2 hours; Refrigerated (2-8°C): 7 days; Frozen (-20°C or lower): up to 6 months. Avoid repeated freeze-thaw cycles. Ship on dry ice if referring to another laboratory.
Hemolysis max
200
TAT
72–336 hours
Order
routine

Why This Test Is Done

Your doctor may order this test if you have symptoms such as memory problems, confusion, seizures, or unexplained movement disorders. These symptoms can sometimes be caused by an autoimmune response targeting the nervous system. The test checks for specific antibodies in your CSF that may indicate an underlying condition like CASPR2-associated limbic encephalitis.

What to Expect Before the Test

No special preparation is needed. The test involves a lumbar puncture (spinal tap), where a small amount of CSF is collected from your lower back. This procedure is usually done in a hospital or clinic setting and may cause mild discomfort.

What the Results Mean

Positive results for CASPR2 antibodies in CSF can support a diagnosis of autoimmune neurological disorders. However, results alone may not confirm a diagnosis; they are often used alongside clinical findings and other tests.

Possible Conditions Linked to Positive Results

Positive antibody levels may be associated with conditions such as limbic encephalitis (a type of brain inflammation), paraneoplastic neurological syndromes (caused by cancer), or other autoimmune-related neurological diseases.

Reference range

Negative: titer <1:10 (cell-based assay); <1:100 may be considered borderline. Positive results are reported as endpoint titers (e.g., 1:10, 1:32, 1:100, 1:320, 1:1000). Reference values may vary by performing laboratory and assay methodology.N/A

Specimen: csf

No fasting required. Patient should be informed about the lumbar puncture procedure, including risks of headache, infection, and bleeding. Informed consent is required prior to CSF collection.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

CSF Anti-CASPR2 Antibody

Frequently asked questions

What does it mean if my test results are positive?
A positive result suggests the presence of CASPR2 antibodies in your CSF, which may indicate an autoimmune process affecting your nervous system. This finding often prompts further evaluation, including additional tests and clinical assessment to determine the exact cause and guide treatment.
Can this test be used to diagnose all neurological disorders?
No, this test is specific for CASPR2 antibodies and is used primarily to support a diagnosis of certain autoimmune neurological conditions. It is not a standalone test for all neurological disorders and should be interpreted by a healthcare provider in the context of your symptoms and other test results.
How often will I need this test?
The frequency of this test depends on your symptoms, medical history, and ongoing evaluation by your healthcare provider. They may recommend retesting if symptoms change or if further investigation is needed.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy